There are numerous applications where it is desirable to position a trailer such that the floor of the trailer is level with respect to the ground below it. Mobile homes, sometimes called house trailers, are the most common example. Mobile office space type trailers are another example. Obviously, in most cases it is equally desirable to maintain this position of level.
Typically, when a trailer is installed in a permanent, or semi-permanent, location, it is leveled by placing the base or frame of the trailer on pillars spaced along the frame between the frame and the ground or other surface beneath the trailer. With mobile homes, the pillars typically comprise concrete blocks. Conventional methods typically used during the initial leveling process can be quite complex, requiring the assistance of technicians skilled in the use of specialized instruments such as a surveyor's transit. An important feature of the present invention is its suitability for use by relatively unskilled persons.
With the passage of time, there is a tendency for trailers to deviate from the initial position of level due to settling of the surface beneath the trailer and other causes. This is a particular problem with very long and very heavy trailers such as mobile homes. In addition to the obvious aesthetic benefits of maintaining the level of a trailer which is used as a dwelling or office, it is important to maintain the level to keep doors and windows in proper alignment. It is also advantageous to maintain the level of the floor beneath level-sensitive appliances such as refrigerators, washing machines, and clothes dryers. The system of the present invention includes a feature whereby deviations from an initial position of level, as well as the corrections required to correct for such deviations, are visually indicated.
Numerous liquid leveling systems have been developed in the past. Known prior art is illustrated in the following United States patents:
______________________________________ U.S. PAT. NO. INVENTOR ISSUE DATE ______________________________________ 386,924 A. Kegel July 31, 1888 451,680 A. Gamble May 5, 1891 915,084 R. Eberhard March 16, 1909 2,532,883 P. L. Bennett, et al. December 5, 1950 3,015,167 J. M. Chapman January 2, 1962 3,132,428 H. O. Haissig, et al. January 12, 1962 3,137,091 H. Clare, et al. June 16, 1964 3,144,234 K. Artmann August 11, 1964 3,310,880 A. W. Watts March 28, 1967 3,680,216 L. W. Hallanger August 1, 1972 3,768,766 A. O. Bain October 30, 1973 3,910,576 X. Leonhart October 7, 1975 ______________________________________
While these leveling systems, as a general rule, incorporate one or more liquid containing members, the systems generally are designed to provide a representation of whether two points are level, one with respect to the other.
Contrawise, the present invention includes as an object a feature whereby relative elevations at a plurality of positions horizontally spaced along the base or frame of a trailer are visually indicated to facilitate leveling of the trailer during setup.
Further it is an object of the present invention to provide a measuring system which includes a feature whereby deviations from the initial plane of level are indicated at a plurality of positions spaced along the base or frame of a trailer.
It is another object of the present invention to provide a measuring system for facilitating the correction of deviations from level of a trailer which result from settling.
Another object of the present invention is to provide such a measuring system which can be readily and inexpensively manufactured and maintained.